Control apparatus for prime movers



Dec. 28, 1948. R. R. STEVENS CONTROL APPARATUS FOR PRIME MOVERS I 2 Sheets-Sheet 1 Filed May 22, 1943 .v q MW t m J .3 S m wm m \fo t .6ncoomm o n o 6E m 8 H n w mm. m O w i w 0: 3 w i Y Em Rm Dec. 28, 1948. R. STEVENS 2,457,510

CONTROL APPARATUS FOR PRIME MOVERS v I Filed May 22, 1943 2 Sheets-Sheet 2 I ..-JENTOR E yR LSzevens ATTORNEY Patented Dec. 28, 1948 CONTROL APPARATUS FOR PRILIE MOVERS Roy R. Stevens, Forest Hills, Pa., assignor to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application May 22,, 1943, Serial No. 488,040

;6 Claims.

This invention relates to control apparatus for prime movers and more particularly to means for controlling the starting, reversing and speed or power output of a plurality of prime movers, such as of the Diesel type.

In ships provided with a plurality of engines of the reversible Diesel type connected to individual propellers it is desirable to selectively control the engines either individually or in multiple in order to obtain a relatively high degree of maneuverability of the ship, such as movement either forwardly or in an astern direction under power of any desired number of the engines, rapid turning of the ship, and reversal of the direction of movement of the ship.

One object of the invention is therefore the provision of the control system for a plurality of reversible prime movers such as Diesel engines which provides for selective individual or multiple control of the engines to accomplish the above results.

Another object of the invention is the provision of such an apparatus providing for either individual or multiple control of the starting, the reversing and speed or power output of a plurality of Diesel engines.

Another object of the invention is the provision of such a control apparatus embodying arrangements which are operative automatically to nullify the multiple control upon operation of the individual control, and vice versa, so as to avoid interference between the two difierent controls.

Still another object of the invention is the provision of such an apparatus particularly adapted for controlling Diesel engines from a remote station, such as the pilot house or bridge of a ship.

A further object of the invention is the provision of a remote pneumatic control system for selectively controlling the starting, reversing and the speed or power output of a plurality of Diesel engines.

Another object of the invention .is the provision of a control apparatus for a plurality of Diesel engines embodying means for adjusting the speed or power output of one of the engines relative to another for the purpose of either obtaining a specific desired speed or output of said engine, or for synchronizing the speed or power output of said engine with that of another engine.

Other objects and advantages will be apparent from the following more detailed description of the invention.

In the accompanying drawings; 'Fig. 1 is a diagrammatic view in outline of a control system embodying the invention; Fig. 2 is a sectional Description In the drawings, the dot and dash line enclosures designated by reference numerals I and 2 indicate two reversible Diesel engines each of which is provided with the usual starting and reversing control shaft 3 and governor control shaft/l.

For illustrative purposes only, each of the starting and reversing control shafts .3 may, as indicated by legends .in Fig. 1, have a neutral or Stop position for stopping the engine. .Each shaft 3 may be rotated from this Stop position in the direction of the legend Ahead to Primary startf and Secondary start positions for placing the engine in motion in a direction such as to cause ahead movement of a ship. After the engine is thus started, the shaft 3 maybe turned to an adjacent Running position in which it will then remain until it is subsequently desired to stop or reversethe engine. Each shaft 3 may also be rotated in the opposite direction from Stop position, that ism the direction of the legend Astern to Primary start and .Sec-. ondary start positions for placing the engine in motion in the reverse direction and then to an adjacent Running position ,in which it will be left until it is subsequently desired to stop or reverse the direction of operation of the engine.

Each of the governor control shafts 4 .is operable to govern the supply of fuel to and thereby the speed or power output of the respective :englue and may theretore have an engine idling position, in which it is shown in the drawing, to provide for operation of the engine at idling speed, and may .be rotatable from this idling position :a counterclockwise direction, as viewed in Fig. '3, for increasingthe fuel supply 'to'the engine to increase the speed or power output thereof. Each shaft 4 may be lournaled in a bracket 5 associated with the respective engine and-may carry at its end the usual hand wheel 6 for manually adjusting the engine fuel supply.

The parts so far described and the means controlled thereby may be of any conventional type well known to those skilled in the art and a further disclosure and description thereof are not essential to a clear understanding of the invention.

According to the invention means are provided for adjusting either individually or in unison in-' dependent means such as the starting and reversing shafts 3, and the governor control shafts l of the two engines I and 2. The arrangement for controlling the starting and reversing shafts 3 will be first described.

Control of Starting and Reversing Shafts 3 For adjusting the shafts 3 iri'enginesl and 2, I associate therewith like power devices, prefer-v ably in the form of fluid motors I and la respectively, each of which may embody a reciprocable member 8 connected by a rack 9 and gear ID to 7 the respective shaft. The motors may be of any desired construction, as for example like the motor fully disclosed and described in my copending application Serial No. 463,792, filed October 29, 1942, Patent No. 2,383,278, August 21, 1945, whichembodies means operative to position a member, like the member 8, in accordance with pressure of fluid provided in either one of two pipes,like pipes I I and I2 connected to the motor I, and pipes Ila and I2a connected to the motor la. The pipes II and Na may be called forward pipes, while the pipes I2 and IZa may be called reverse pipes.

With all of these pipes open to the atmosphere the motors 'I and Ia will cause the members 8 to assume a neutral position, as shown in the drawrings, for positioning the respective starting and reversing shafts 3 in their Stop positions. When fluid at a certain maximum pressure is provided in pipes II and Na, the motors I and Ia willcause the members 8 to operate racks 9 and gears II) to turn the respective starting and re-- versing shafts 3 in the Ahead direction tothe Primary start positions. When the pressureof fluid in these pipes II and Na is at a certain lower degree the motors I and Ia will cause the respective} shafts 3 to assume their Secondary start positions at the Ahead side offStop, and when at a still lower degree said motors will cause the shafts 3 to assume their adjacent Rum ning positions. On the other hand, if thesame difierent degrees of fluid pressure is providedin the reverse pipes I2 and I2a the motors I and "Ia will operate to rock the shafts 3 in the Astern direction to corresponding positions. A further description'of the structure and operation of the fiuidmotors'l and Ia is not deemed essential to 20 fluid at a pressure determined by the position of the lever, while maintaining the other pipe open to the atmosphere. The lever may have a neutral position in which it is shown in the drawing for opening both pipes l9 and 23 to the atmosphere. Movement of the lever in a clockwise direction from neutral position will provide fluid in pipe I9 at a pressure corresponding to the diutance said lever is away from the neutral position, While movement in the opposite direction from neutral position will provide like pressures of fluid an understanding of the invention and hence will be omitted.

At a remote control station, such as on the bridge of a ship, I provide two independent selflapping manually o erative control devices, I5 and I6, for individually controlling the motors I and la, respectively, and a manually operative master self-lapping control device IT for controlling both of said motors in unison or multiple.

The control devices I5 and I6 may be of identical construction, as well as the control device I! with but one exception which will be later described, and all of these devices may be generally similar, if desired, to a corresponding device fully disclosed in the copending application hereinbeiore referred to, in view of which a detailed disclosure and description of the devices is not essential in the present application to an understanding of the invention.

Briefly, the control device I 5 comprises valv lever I 8 for providing in either of two pipes I9 or in pipe 20.

The control device It is operative to control pressure of fluid in tWo pipes 2| and 22, while thecontroldevice I1 is operative to control pressure of fluid in two pipes 23 and 25, in accordance with operation of the control levers it of said devices, in the same manneras just described in connection with control device I5;

. Fluid under pressure for supply to the pipes It to 24 is conducted to the control device IE, it and IIfrom any suitable source by way of a supply pipe I4.

The pipes I9 and 23 are connected to opposite ends of a double check valve device 25 the side outlet of which isconnected to pipe I i. The pipe 23 is also connected toone end of a double check valve device 26, the Opposite end of the device being connected to pipe 2!, while the side outlet of said device is connected to pipe I la. The pipe 2% iseonnected to one end of each of two double" Each of the double check valve devices 25 to 28 may, as shown in Fig. ,4 of the drawings, comprise a' casing containing a double ended check valve 29 arranged to control communication between the two pipes connected to the opposite ends of the device and a passage 30 which is in constant communication with the pipe connected to the side of the device. The check valve 29 will be moved to the position shown in Fig. 4 by fluid supplied through the pipe open to the right hand end thereof forthereb'y opening communication between such pipe and passage 38 and for closing communication between passage 30 and the pipe open to the opposite end of the check valve. If fluid under pressure is supplied to the pipe open to the left hand end of checkvalve 29, said check valve will be shifted to its opposite position for opening communication between said pipe and passage 30 and for closing communica tion between passage 30 and the pipe open tothe right handend of the check valve.

From the. above description, it will now be seen that with levers I8 of the control devices I5, I6 and IT in their neutral positions as shown in the drawings, the pipes II and I2, and Ila and I20, will all be open to'the atmosphere through either one or another of said devices, whereby the motors 1 and la will position the starting and reversing shafts 3 of" the two engines in their Stop positions, a

If lever I8 of the control device I5 is now moved from its'neutral position ina clockwise direction fluid under pressure will be supplied to pipe I9 and thence through double check valve device 25 and ,pipe II to the fluid motor land cause said motor to operate to turn the starting and reversing shaft.3,of. the engine I out of fStop position in the direction of the legend Ahead and to a position corresponding to the pressure of fluid provided in pipe I l and thereby to the position of lever 18 of the contrdldeviee 1B. As-above described, the motor I will operate to position the start and reversing shaft '3 of engine 1 in accordance with pressure of fluid in pipe l i and that certain definite degrees of pressure are required in said pipe in order for the motor to position said shaft in its difier'ent positions at the flheacl side of its Stop position. These definite pressure will be provided "in pipe H in definite posttions of lever 8 of the control device tothe right of its neutral position shown. Thus it the lever 18 ofthe control device I5 is moved to the position required for providing fluid in pipe H at the pressure for causing motor 1 to operate shaft 3 in a clockwise direction "to Trimary' s'tart position, said shaft will be so positioned to cause starting the engine. Return of lever 18 of control device i5 toward its neutral position to definite positions will provide in pipe H the different degrees of fluid pressure for causing the motor to return the start and reversing shaft 3 of engine I to the Secondary start and Running positions, as desired. Return of lever 18 of device I 5 toitsneutral position with a consequent completerelease of fluid from pipe H, will cause motor 7 to return the start and reversing shaft 3 to its Stop position.

Movement of lever 1-8 of the control device IS in a counterclockwise direction to position's to the left hand side of its neutral position will provide fluid in pipe and thence through the double check valve device 2 1 and pipe l 2 in the motor lto cause operation of said motor to position the start and reversing shaft 3 of engine 1 at the Astern side of "-Stop" position in accordance with the degree of such pressure. Thus movement of the lever I 8 of the control device l5 to selected positions at the left hand side or its neutral position may cause operation of the motor 7 to tum the start and reversing shaft '3 to any selected one of the positionsat the Astern side of" Stop indicated by legends in the drawing. Return of the lever l8 of'the control device 15 to its neutral position will cause motor 'lf'to return the start and reversing shaft 3 to its Stop 'position. I

Pipes 2 and '22 extending from the manual control device Hi are, as above described, connected through the double check'valve devices '26 and 28 'to pipes l'l'c and 12a respectively, leading to the unotor'la and from the above description of operati'on of the control device l5 and motor 1,111; will be :apparent that by movement of lever ll-of the control device 1 6 ineither one direction or the opposite direction from its neutral position shown, todifferent definite positions, the fluid motor 7a maybe caused to operate to position the :"startand reversing shaft 3 of engine 2 in any. selected one of its "different positions indi- Jcated by legends in the drawing.

it will now be seen that "the two independently operative manual "control devices 15 and 16 provide f or individual :control of the starting, reversingand running of the two engines l and 2.

If lever t8 of thema'ster control device l=1 is moved out of its neutral position in a clockwise direction fluid will bessupplied to pipe '23 and thence through :both double :check "valve devices 5 and 26 to pipes 'H and thin and thus simultaneously to both of .the fluidmotors 1 and "la, and it will be'seen that by proper positioning of said lever the start-and reversing :shafts 3 of :both engines of'the like positions at the "Ahead side of their Stop positions.

On the other hand, if the lever 18 of the master control-device {T is moved from neutral position in a counterclockwise direction fluid will be supplied to pipe 24 and thence through both double" positioning of the starting and reversing shafts 3 of both engines I and '2 and may therefore cause simultaneous starting of both engines in either one direction or in the reverse direction. Return of the lever 18 of the master control device II"! to neutral position will effect opening of both pipes Band 24 and thereby of pipes I I. and [2,and I la and [2a to the atmosphere for causing operation of the fluid'motors 1 and 1a to turn the two starting and reversing shafts 3 to their neutral position.

In order .to prevent interference between the individual and the :master control of the two engines it is necessary that the lever I8 of the master control device I! be maintained in its neutral position shown in the drawing while the engines :are being controlled individually by the control devices 15 and 16. It is also necessary that the levers l8 ofithe individual control devices l5 and Hi be maintained in their. neutral positions shown in the drawing, while the two ongines :are being controlled by the master control device IT. This is accomplished in a. manner which will now be described. I

Twos'top devices 33 and 34 are associated with the control device [7 at one side of the lever l8 while two like stop devices '35 and 3B are associated with said control device at the opposite side of lever 18. As shown in Fig. 5, each of these stop devices may comprise a piston 3] having at one side a pressure cl'lamber 3.8 and provided with a rod 39 projecting from the opposite side in alignment with the lever t8 and for movement in the same direction as said lever. A spring! encircling the rod 39 acts on the piston '31 for urging it to a retracted position shownin Fig. 5 when chamber 38 is open to the atmosphere. With the pistons 31 in the stop devices 33 to-36 in the retracted positions, the rods 3$ will be positioned to allow full movement of the respective lever 18in either direction from its neutral position for control-ling the fluid motors I and la as above described.

The pistons 31 and rods 39 of the stop devices 33 and 3 5 are adapted to he moved against springs 40 upon supply of fim'd under pressure to the pressure chambers 38 to positions which may be defined by engagement between a'shoulder 43 provided on each of the rods and the end of the device engaged by said spring. "With the pistons 3 and rods 39 thus positioned the lever E8 of the master control device ll will be held against movement outof neutral position.

The pressure chambers 33 of the two stop oevices 33 and are both connected by pipe ll to the side outlet of a double check valve device 12 the opposite ends of which are connected to p'ipes lll and 2 0. "This check valve device may 'be identical to structureshown in Fig. 4.

I and 2 may be caused to move in unison to any '75 With lever 18 of the individual control device 1'5 7 in its neutral position shown opening both pipes I9 and 29 to atmosphere, pipe AI and thereby pressure chambers 38 in the stopdevices 33 and 35 will be vented to allow the pistons 31 in said devices to occupy the positions shown in order that the master control lever I8 may be operated to control the two engines in unison, if such is desired. However, if lever I8 of the individual control device I is moved in eitherdirection out of its neutral position shown, the consequent supply of fluid under pressure to either of pipes I9 or 29 will cause flow of fluid under pressure therefrom through the double check valve device 42 to pipe M and thence to pressure chambers 38 in the two stop devices 33 and 3 5 which will operate the pistons 37 therein to move therespective piston rods 39 to the positions defined by shoulders 43 on said rods. In this position of rods 39 of the stop devices 33 and 35, the ends of said rods will engage or substantially so the opposite sides of the lever I9 of device I1 and hold said lever against movement out of neutral position and thus prevent operation of the master control device I! when the individual control device I5 is being operated to control the motor I.

The two stop devices 34 and 36 associated with the master control device II are provided to act in the same manner as the stop devices 33 and 35, upon operation of the individual control device I6. This is accomplished by connecting the pressure chambers 38 in the two stop devices 34 and 36 by a pipe 44 to the side outlet of a double check valve device 45, like the double check valve device 42, and which has its opposite ends connected to pipes 2| and 22 leading .to the individual control device I6. It will thus be seen that upon operation of the individual control device I6, the lever I8 in the master control device I! will be'held in its neutral position. I

With lever I8 of both individual control devices I5 and I6 in their neutral positions, the stop devices 33 to 36 will be conditioned to allow movement of lever I8 of master control device I! as will be apparent.

Associated with the individual control device I5 are two stop devices 4! and 48 while two like stop devices 52 and 53 are associated with the control device I6. These stop devices may all be identical to the devices 33 and and are connected to a pipe 49. sure to pipe 49, the stop devices 41, 48, 52 and 53 are operative to hold the respective control levers I8 against manual movement out of their idling positions. When the pipe 49 is relieved of fluid pressure or opened to the atmosphere, the

stop devices 41, 48, 52 and 53 will permit movement of the respective levers It for controlling individually the motors I and Ia.

The pipe 49 is connected to the side outlet of a double check valve device 50 and the end outlets are connected to pipes 23 and 24 leading to the master control device IT. The double check valve device 50 is like any of those above described, so that upon operation of lever I8 of the master control device I! to supply fluid under pressure to either of pipes 23 or 24, fluid under pressure will flow to pipe 49 and actuate the stop devices 41, 48, 52 and 53 to hold the levers I8 of the individual control devices I5 and I6 against movement out of their neutral positions. With the master control lever I8 in idling position opening the pipes 23 and 24 to atmosphere, the pipe 49 will also be opened to the atmosphere in order to allow individual movement of levers I8 of the control devices I 5 and I6.

Upon supply of fluid under presagainst turning as by pin 63.

From the above descriptionitwill now be een thatwhen lever, I8 of the master control device I and la tostartorto. reverse engines I and 2,,

as desired, and during suchoperation the master control lever I8 .is held against movement out of its, neutral position tothereby prevent ,interierence of the mastercontrol device with operation of the individual, control devices. It will also beseen thatwhen the lever I8 ofthe master control device I1 is moved: out of its neutral position-for controlling the-starting and reversing ofthe engines Iv and 21m multiple, the levers, I8 of theindividualcontrol devices I5 and I6 are held against movement out of their neutral positions in j order to avoid interference therefrom.

, Control of gooernorshafts 4 v -Between the bracket} and the speed control wheel 6 and mounted on the governor control shaft 4 .associatedwith each of the engines I and Z'are two spacer elements 60 and BI and anintermediate beveled gear 62, The element 99 is interposed between oneencl. oi the gear 62 and bracket 5, while the element 6 I-, is interposed be--. tween the opposite face of the gearand the wheel 6. The element 60 is secured-to the bracket 5 p The element 6| and-gear 62 arejournaled on the shaft 4 and secured to turn together by a pin 64., I

. r Theelement BI is providedwith a radial arm 65 the end of whichis connected to a spoke 56 of wheel 6 by an extensible linkBI. The'link 61 comprises a cylinder containing a piston 68 having at one side a pressure chamber 69 and at the opposite side a nonspressure chamber III. A rod II, secured at one, end to the piston 68, projects throughcharnber I0 and one end of the cylinder and the outer endoi this rod'is .pivotally connected by a pin 12 to the end ofarm 65. Pro- 'jecting fromthe oppositeend of the cylinder, is

ed by removable pinMto the spoke66 of wheelfi.

The non-pressure chamber 10' contains a coil spring I5 which encirclesthe piston rod II and is supported at one end by the end of the-casing. The opposite endoithe spring acts against the piston 68,.this springbeing underpressure for urging said pistonin the direction of chamber 69 to a position defined by contact between'the piston and the end of, said chamber. Normally, thespring I5 holds the piston 58 in contact with the end of the cylinder, as shownin the drawing, to thereby provide,in' efiect, a rigid operating connectionbetwe'en arm 6510f. member GI and spoke of the wheel, wherebyythewheel may be turned by movement of arm 65. p 7

The. pressure chamber 69 ineach-pf the links 6! is connected by. a,fleXible conduit I6; to an annular cavity II provided in member 6| around the outer surface of the respective. governor control shaft 4. JThe-shait 4: in turn is provided with a passage 18, fone end of which is. in constant communicatiomwith cavity '11, while the opposite endis in constant registration with anannular cavity I9=provided. in'member 60 around the periphery of the shaft The cavity 19 in the structure associated with engine I'is connected by a pipe to a so-called verniercontrol device 8|, while cavity I9 in the structureiassociated with engine 2 is connected by pipe 82 to the'control device 8|, for reasons which will hereinafter be brought out. 1 I

The bevel gear 02 associated with each governor control shaft 4 meshes with a drive gear 04 which is secured on one end of a rod 85 journaled in a projection 36 of the respective bracket 5. Below the projection 85 the shaft 85 is provided with a screw-thread which meshes with aninternal screw-thread provided. on a reciprocatory rod 87. The rod 8'! projects from one side of a piston 88 contained in a cylinder 89 and is pro-- vided along one side longitudinally thereof with a slot 90 into which projects a tongue 9I forming At the opposite side of piston 33 is a pressure chamber 95 conn cted to a pipe 98 through which fluid under pressure may be supplied to and released from said chamber for positioning the piston 88 against the spring 94. When fluid under pressure is supplied to chamber 95 to a degree which exceeds the opposing force of spring 94 v the piston 88 will move against said spring to a position in which the opposing forces become equal. This movement of piston 88 and thereby of rod 8'! will act to turn. the shaft 85 and gears i and E2 and thereby the wheel 6 through the medium of link Bl to a position corresponding to the pressure of fluid acting in chamber 95. With chamber 95 open to the atmosphere the wheel 6 f may therefore assume the engine idling position,

while upon supply of fluid to said chamber the wheel 6 will be turned out of idling position to a position corresponding to the pressure of such fluid. It will thus be seen that by varying the 10 is connected to pipe I03, while the side outlet of this double check valve device is connected-to pipe 98 leading to cylinder 89 associated with the engine 2. The double check valve devices I05 and I00 may be identical to those hereinbefore described, and as shown in Fig. 4.

With the structure just described it will be seen that the speed of engines I and 2 may be individually controlled by operation of the individual control devices 98 and 99, respectively, or jointly controlled by operation of the master control device I00.

Associated with the master control device I 00 are two stop devices I01 and I08-containing pistons (not shown) arranged to be operated by fluid pressure for holding the master control lever l0l against movement out of its idling position. These stop devices may be substantially like the stop devices and 36 associated with the master control device I1 hereinbefore described, and'are connected respectively to pipes l02and I03 connected to the individual speed control devices 98 and 99. It will thus be seen that when the individual speed control devices 98 or 99 are operated to control the speed of the respective engines one or the other or both of the stop devices I0! or I08 will operate to hold the control lever I0! of the master speed control device I00 against movement out of its idling position. A stop device I09 associated with-the individual. control device 98 is connected to pipe I04 leading to the master control device I00. A like stop'device H0 is associated with the individual control device 99 and is also connected to pipe I04, whereby upon operation of the master control device I00 to control of the speed of the two engines in unison the stop devices I09 and H0 will operate tohold levers IOI of the individual control devices 98 pressure of fluid in each pressure chamber 95" from atmospheric pressure to a desired degree above atmospheric pressure, the respective wheel 6 may be adjusted to any desired position for 0btaining a desired speed or output of the respective engine exceeding that obtained. in the idling position.

For individually controlling the two speed. control pistons 08 I provide two independently operative speed control devices 98 and 09, while for controlling the operation of these pistons in unison I provide a master speed control device I00.

The control devices 98, 99 and 800 may be generally like the manually operative starting and reversing control devices I5 to E1 except that each comprises a lever I! having no neutral posit on. The individual speed control devices 98 and 89 are arranged to vary pressure of fluid in pipes I02 and E03, respectively, while the master control device I00 is arranged to vary the pressure of fluid in a pipe I'04i The lever I00 of. each of these control devices has a normal or engine idling position in which it is shown for opening the respective pipe to atmosphere and is adiusaable out of the idling position to positions. at the righth hand side thereof to provide fluid in the respective pipe at pressures corresponding to the distance the lever is away from the idling positions.

The pipes I02 and I04 are connected to opposite ends of a double check valve device I05 the side outlet of which is connected tov pipe 98 leading to cylinder 83 associated withthe engine. 8.

.- Eipe I04 is also connected to one end of a double check valve device I08 the opposite end of which and 09 in their engine idling positions.

As so far described it will be noted that the speed of the engine is adjusted through the medium of the adjustable or extensible links'fi'l connected to the speed control wheels 5, said links, in effect, acting under this condition'like rigid links. 1

In order to effect a minor adjustment in speed or output of either of the engines I or 2 relative to the other, as after adjustment of the speed by operation of one or another of the speed control devices 98, '99 or I00, fluid under pressure may be supplied to pressure chamber 69 inthe respective extensible link 61, and when this pressure becomes sufiicient to overcome the opposing force of spring I5 on piston 68, the cylinder mounted on the piston will move relative to the piston and thereby turn the respective'wheel 6 relative to the arm as adjusted by the. respective manually operative speed control device. to thereby increase the speed or power output of the .engine in accordance with the pressure of fluid supplied to pressure chamber 59.

The pressure of fluid effective in chamber .69 of the extensible links 51 associated with the two engines is arranged to be controlled through pipes and 82 by the vernier control device .8I. This device may be substantially like the start and reversing control devices I5 to IT but without the stop devices associated with the latter. The device 8t may therefore comprise an operating lever III, having a neutral positionjfor opening both. of the pipes 80 and 82' to the atmosphere. This lever may be'moved from neutral position in a clockwise direction" for supplying fluid to pipe 80'' at a pressure proportional "to the extent of such movement. The levermayalso be movable in'a counterclockwise directionfrom neutral position for supp-lying fiuid to pipe 82 at a pressure proportional to the extent of such movement.- Thus, by, properoperation of lever Ht, fluid at any desired pressure may be provided in pressure chamber 69 of'link 61 associated with either engine for providing ;a desired increase in speed or power output of said engine. 7 e

The extensible links 61 are connected to the respective wheels Gby removable pins 14,. so that means when the multiplecontrol means is being operated, and vice versa, 'so as to thereby avoid, under all circumstances, interference of either of said control means with the other when controlf ling the engine or engines.

is fluid under pressurev which is particularly The control medium adapted for prompt and accurate remote control. Anovel arrangement is provided for effecting a minor change in speed of either engine relative to the other in order, for instance, to bring the operation of the two engines into synchronism.

Having now described the invention, what I claim as new and desire to secure by Letters Patentis: 1

1. In combination, a device adjustable by fluid under pressure, two control means individually operable to provide'fluid under pressure for controlling said device, and means operable by fluid under pressure, p'rovided'by one of said control means for controlling said device, to. prevent op- ,eration'of the other control means.

2. In combination", a plurality of "adjusting means adjustable by fluidunder pressure, a master control device operable to effect a supply of fluid under pressure to all of said adjusting means simultaneously for adjusting said adjusting means, an individual control device for each of said adjusting means operable to effect a supply of fluid under pressure to the respective adjusting means for adjusting same, interlock means operable by "fluid under pressure suppliedby op- I eration of said master control device to prevent operation Of the individual control devices and operable upon release of such fluid under presvsure to provide for operation of said independent control devices, and other means operable by fluid under pressure, supplied by any one of said individual control devices for controlling said adjusting means, for rendering said master control 4 device ineffective to supply fluid under pressure for controlling said adjusting means and effec tive to release fluid under pressure from said interlock means. r v

3. In combination, a plurality of adjustable devices, a master manually operable control devicearranged to control said plurality of adjust-able devices in unison, a plurality of individual manually operable control devices, one'for each of said adjustable devices, separately operable to control therespective adjustable devices,

movable means controlled by said individual con-.

trol devices and operable upon operation of any one or moreof said individual control devices to control the respective adjustable device or devices to render said master control device ineffective to control'said adjustable devices, said movable means being ineffective to control said individual control devices, and other movable means controlled by said master control device,

a master control lever, each of said levers having a normal position and being movable outof said normal position, movable means associated with said master lever for holding same against movement out of said normal position, other movable means associated with said individual levers separate from and movable relative to the first named movable means for holding said individual levers against movement out of their normal positions, means controlled by said master lever operable upon movement thereof out of normal position to effect movement of said other mov-" able means relative to the first namedmovable means to render said other movable means effective and operable in said normal position to render said other movable means ineffective, and means controlled by said individual control levers operable upon movement thereof out of normal positionto effect movement of saidfirst named movable means relative to said other movable v means,to render said first named movable means effective and operable in the normal position of said individualv levers to render said first named movable'means ineffective, said master lever having no control over said first named movable means, and said individual levers having no control over said other movable means.

5. A control apparatus comprising two pipes, a control valve device for each of said pipes for regulating pressure of fluid therein, each control valve device comprising a lever having a normal position to effect operation of the respective control valve device to provide one pressure condition in the respective pipe and :being movable out of said normalposition to effect operation of the respective control ,valve device to provide a different pressure condition in the respective pipe, means associated with each control valve device subject to and controlled by pressure of fluid provided onl in the pipe connected to the other control device, said means being operable when subjectto said different pressure condition to render the lever of the respective controlv device immovable from its normal position and when subject to said-one pressure condition movable from its normal position.

6. A control apparatus comprising three pipes, a separate control valve device connected to each of said pipes and operable to regulate the pressure of fluid therein, fluid pressure controlled means associated with each of twoof said cona double check valve device connecting said separate fluid pressure controlled means to the two 13 pipes connected to said two control valve devices and operable to provide in said separate fluid pressure controlled means fluid from the one of said two pipes which is supplied with fluid-at the higher pressure, each fluid pressure controlled means comprising means operable when subject to fluid at a pressure exceeding a certain degree to render the respective control valve deviceineffective to regulate pressure of fluid in the respective one of said pipes and each fluid' 'pressure controlled means further comprising means operable upon a reduction in pressure in the respective pipe to said certain degree to render the respective control valve device efl'ective to regulate pressure of fluid in the respective pipe.

ROY R. STEVENS.

14 REFERENCES CITED The following references are of record in the file of this patent:

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